Expansible rotary drill bit



March 13, 1951 A. w. KAMMERER 2,545,032

- EXPANSIBLE ROTARY DRILL BIT I Filed July 29, 1946 2 Sheets-Sheet 1 I ATTaQn/EY.

Patented Mar. 13, 1951 UNITED STATESPATENT OFFICE Archer Kammerer, Fullerton, Calif Application July 29, 1946, Serial No. 686,806

4 Claims. (01. 255-71) rhis invention relates to drill bits, and more i particularly to rotary bits of the expansible type for drilling or reaming holes below well casing greater in diameter than the inside diameter of the casing through which the bit is capable of v It is an object of the present invention to provide an expansible well drilling bit, whose cutters are expanded and held outwardly by mechanisms having increased wear resistance, wear distribution, and longer life; thus offering greater assurance against the drilling of an undersized hole, increasing the footage drillable by the bit, and decreasing the extentof maintenance and repair required on the drill bit following its removal from the well bre. 3 ..A further object of the invention is to obviate the-necessity for transmitting drilling torque through. the-device which holds outwardly the cutters of an expansible rotary well drilling bit.

Another objectof the invention is to provide an expansible well drilling bit embodying a device. for-- holding bit cutters outwardly, which device is capable of automatically-adjusting itself to furnish maximum eifective contact surfaces betweenit and the cutter supports;

The invention has other objects which will become apparent from a consideration of the I several embodiments shown in'the drawings accompanyingand constituting part of the pres- .ent specification. These forms will now be described in detail to illustrate the general prin- Figure 2 is a longitudinal section of the drill bit on an enlarged scale, with parts shown in retracted position for lowering through the well bore;

Figure; is a view similar to Figure 2 with the Iliiaits shown in: expanded position;

Figureiisa cross-section taken. along the line it-4 of Figure 2;

Figure 5-is a cross-section-taken along the line 5-5 i'n Figure 2; figure 6 i a partial longitudinal section taken ii. new l e-.E-i ni'i r I 2 Figure '7 is a partial cross-section taken along the line 1-1 in Figure 3; Figure 8 is a view similarto Figure 7 of a modified form oflock device;

Figure 9 is a view similar to'Figure 3 of a ified form of the invention; and I Figure 10 is a cross-section taken along the line Ill-I0 in Figure 9. M

As shown in the drawings, the rotary drill bit A is attached to a string of drill pipe B, by means of which it is lowered through a well casing C in a well bore to a point below the casing shoe D at which enlargement of the bore hole is to commence. The drill bit preferably has a pilot bit 10 at its lower end for centering the bit in a hole {that may have already been drilled, or for drilling the central portion of new hole in the absence of pre-existing hole. The main portion ofthe bit is capable of enlarging the bore hole by producing and operating upon aformation shoulder E, as hereinafter described. r

The upper end of the bit consists of a driviing mandrel I I, whose upper pin I 2 isthreadedly connected to a sub l3 forming the lower end of the drill pipe string B. .This mandrel includes an upper kelly or drill stem member l4 slidably splined to the main body l5 of the hit. As disclosed in the drawings. the exterior I4a of. the kelly is hexagonal in shape and is telescopicallv received in a companion hexagonal socket |5a within the body.- The mandrel has a limited range of longitudinal movement within the body, its upward movement being limited by engagement of an external shoulder IS on the kelly with a retainer ring I! at the upper end of the body, suitably secured thereto as by welding material [8. r

The body l5 has-a plurality of expansibleparts mounted on it, comprising opposed cutter supporting members l9, l9 pivotally carried between bifurcated body arms 21!, 20 on pivot or hinge pins 2!, 2| suitably secured to the arms, a by welding material 22. Each cutter supporting member consists of a depending leg 23, having a bearing supporting pin 24 inclined inwardly and downwardly and on which is rotatably mounted a roller side cutter 25. Anti-friction roller and ballbearing elements 26, 21 are preferably placed between each cutter 25 and bearing pin 24, the roller bearing 26 transmitting radial thrusts and the ball bearings 21 both radial and axial thrusts.

' closed by a plug 29 welded to the pin.

cutter supporting members 9 with cooperabl'e.'.,i

body stop shoulders 34, 34.

After the cutters 25 have been'ex anded outwardly by the expander s rings'3l to the maximum extent, the can be loc ed in this po itionv by a tubular member 35 of the mandrel which 4 drilling area to the top of the well bore. This circulating fluid is also availed of to unlatch the cutter supporting members IS, in the event it is desired to hold them positively in retracted position.

A positive lock may be provided by securing a hook 42 to the inner portion of each cutter supporting member below the lower mandrel guide 4|, and inserting the ends 43 of these hooks in holes 44 in a strip 45 extending across the outlet 35c of the mandrel. The cutting tool A, after "being lowered in retracted position to the point at which. thereaming operation is to begin, may

be released for operation by starting the pumps at the surface of the well bore, which will force fluid down through the drill string B and mandrel I andimpinge upon the latch strip 45, blowis pilote in the kellv l4 and is prov ded withv a lock portion 41, movab e from an upper posit on in transverse alignmentwith inner sup orting member recesses 36, permitting retract on of the cutters, to a lo er osition o osite lugs 3'! formed on and. proiecting inwardlv from the su o t n member legs 23, preventing retraction of the cutters.

The tubular member 35 is conne ted n s ivel fashion to the ke lv 14 to permit rel tive arcua te or rotary move ent t e ebetween. However, the kelly and tubular member are movable to ether for long tudinalv movement in both d rection This is accomplished by provid ng a shou der 39 on the tubu ar member, received within-a o er soc et 14b n the kellv and abutting a companion shoulder Me in the kellv at the u er: end of the soc et. The tubular member 35 has an up er portion 35a extending from the. shou der freely through the ce tral bore 4d of t e ke l with theuo er terminus of the u er member 35 2 received within .an enlarged recess 4c. in the kelly or mandrel p n 12, where a nut-b is threa ed on the terminal portion and bears against-the ba e M) of the up er in rece s He.

The arran ement bet een the tubu ar member 35 and l el v I 4 is such that do nward movement is transm tted from the kellvto the tubular member through the abutting shou ders I40, 39L while upward movement is transmitted to. the tubular me ber throu h engagement of the recess shou er l4) with thelnut 3512. Ho ever; the

nut 3571 does not serve to clamothe tubular member 35 to the kellv 4, butallows relative rotary movement therebetween. J

The mandrel H is normally held in its u er position with resnect to the main body. l5 of the bit and the supporting members i9 by a helical retractor s ring 38 encircl ng the tubular member 35, with its upper end engaging the mandrel shoul er 39 and its lower end engaging asnring seat at the lower end of the hexagonal body soc et l5a. This spring seat 4|i'also serves as an upper bearing guide for the tubular mandrel me ber 35, whose lower end is slidab e within a lower bearing guide 4| below the lugs 31-, which ,is integral with or secured to the de ending body arms 20 of the main body of the bit. The two guides 40, 4| form a spaced two-point support .for the mandrel member 35 andassist it in; re; sist ng inward movement of'the cutter legs 23 to retracted position during the reaming or cutting operation. r g I Circulating fluid can pass downwardly through the string of drill pipe B and through the tubular mandrel H for ejection from its lower discharge nozzle 35c and onto the cutters 25," tov cleanse them of cuttings and flush the latter from the ing or forcing it off the hook ends 43 and permitt ng the spring expanders 3| to shift the supporting arms 3fl inwardlyand the cutters 25 outwardly against the tormation In the operation of the device the tool A is mountedjon the lower end of the drill string B with its parts held in retracted position by the latch strip 45, as shown in Figure 2. In this posit on of operation, the compressed retractor spring 38 holds the mandrel H ,and its Kelly M in an upward position with respect to the body l5, as determined by engagement of the kelly shou der |6 with the body retainer ring ll. With the mandrel infthis positionitslock p rt on 41 iselevated above the -lugs; 3' onthecutter supportin i b 1 bein TWQ EQ. Within the inner recesses 36 in the 'supporting members, which permits-the latterto beheld inwardly against the actionof the expander springs 3|. The tool is lowered through the well casing C, and upon reaching the position in the well bore below the casing shoe D, at which the drilling operation is to begin, the pumps are started at the surface of the well bore and fluid impinged on the latch strip 45, forcing it hydraulically oil the ends 43 of the hooks 42 and releasing the cutting support ng members 9 for outward expansion'under the influence of the springs 3|.

The drill string B is then rotated to rotate the main bit body 5 through the splined kelly and body connectionf lilo, |5ctthe expander springs 3| forcingthe arms 30 inwardlyand the cutters 25 outwardly against the formation. Rotation is continu'edwithout movingthe drill string long'itudinally'untilthe side cutters 25 enlarge the diameter of the hole to the maximum extent, as determined by theeventual' abutting of the support ng memberstop shoulders 33 with the 'comp'an'i on body stop shou ders 34. Thereafter, the drill string is lowered to cause the formation "shoulder E, produced in the well bore by the eutters-"25 under the action of the expander springs 3|, -to-s upport the cutter members 25, I3 and body I5 andjprevent their downward movement;-

Since the body I5 c'an not move downwardly, dri ling" weight imposed on the drilling string B shifts its connected mandrel downwardly within the body 5 against the action of the retractor Spring ni li e. w rsndifi th Kelly. engages the upper-springseatand-guideIU. v This d wnward movement "alsc 'shifts the tubular member 35 downwardlmbecause of the abutting between the kelly and tubular member shoulders "14c; 39', to position the mandrel or tubular member loci: portion 4|oppositeand"in alignment with the lugs 31 on the inner'portions. of the cutter supporting'members19, providing a posithe look by preventing inward movement of the cutters. So long as down weight is imposed on the drill string '13 and the cutters rest on the formation shoulder E, the cutters are prevented from moving inwardly by engagement of their Drilling is continued by rotating the drill bit and imposing the proper drilling weight "on the cutters to .fcause their removal of the formation material and reaming of the hole in a downward direction for the desired extent "or length, When the drill bit is to be retracted and removed to the top of the well bore, all that need be done is elevate the drill string B, which moves the side cutters 25 above the formation shoulder E, and permits the retractor spring d8 to press downwardly on the body I5 and move it, together with the cutter supporting members It, downwardly with respect to the mandrel l I. This ac tion repositions the mandrel lock portion 4'! opposite the supporting member recesses 36 and above their lugs 31 because of the engagement between the pin recess shoulder M1 and tubular member nut b, permitting inward swinging of the cutters 25 and their supporting members I9 when the tool passes back into the casing C upon elevation of the drill string. The cutters 25 and their supporting members I9 will ride the Wall of the casing C during elevation of thcstring until the tool is removed from the top of the well bore.

Pads in the form of longitudinal drag reaming blades 46 can be'formed at the lower outer Sillfaces of the cutter supporting members I9, which will ride the inner wall of the casing and prevent the cutter teeth from hanging up in the casing coupling spaces while the tool is being lowered therein. These pads 125 can be provided in addition to the hooks '42 and latch strip or in place of the latter. When the latching device is used the-tool can be lowered through open hole below the casing shoe D to as far a distance as desired before the reaming'operation commences. If the latch is not provided downward movement of the drill string D can be stopped when the bit passes out of the shoe D and the drill pipe B and bit A rotated to allow the cutters 25 to produce the formation shoulder Eunder the influence of the compressed expander springs 31. Drilling in a downward direction can then proceed, as afore- "mentioned, with the drill string B and mandrel irireferably has flat faces 41a engaging corresponding fiat faces Bid on the lugs 2-! extending inwardly from the cutter supporting members. .-.These iii-at races are preferred t'o lpresent asu'riace'contact between the members, and thus increase: the load carrying capacity cf lock device, enabling it to resist to a greater extent the ractive fcrce or" the formation tending to press the cutters 25 inwardly from their expanded posiitions'; jI'he remaining portions or the tubular:

member 85, namely, the shoulder "39, the upper section 35a above the shoulder, and the portions which ride in the upper and lower bearing guides 4B, 4'! are all circular in cross-section to permit relative rotation, even to a slight extent, between the tubular member v3'5 and the kelly 14 within which it is received.

The relative rotation of the tubular member 35 and its locking portion 41 with respect to the driving kelly Ill is important, since it permits the lock portion 47 to adjust itself with respect to the lugs 33 on the cutter su ports 19 and thus insures a surface contact therebetween. There is a slight play or the supporting members I9 on their hinge pins 2i, permitting a slight angular adjustment of the supporting member about a longitudinal axis with respect to the expander portion 47. In the event that an error has been made in the mounting of the pin 2! in the body 15, the supporting member is may pivot slightly above the longitudinal axis, and this pivoting action,

coupled with the swivel arrangement of the tubu- The inability of the tubular member as to,

swivel or move about the bit axis might merely result in a line contact between the cutter lugs 37 and the lock port-ion 41 of the tubular member, thus producing concentrated wear along both of these parts during their resistance to the formation reactive forces tending to press the cutters 25 inwardly rrom their retracted positions. Such wear would permit the cutters to shift inwardly, and would result in the roduction of a reamed hole of lesser diameter than the diameter desired.

There is still a further advantage to the swivel or relatively osclllatable connection between the tubular lock member 35 and the driv- R'elly l4. Although the kelly is telescopically spli ned to the body l5, a slight amount of relave arcuate movement between them is permitt-ed, because of the working clearances that must be maintained between the hexagonal 'kelly Ma and hexagonal socket l5a in the body. The

rigid attachment of the tubular lock member-35 to the kelly I 4 would result in angularly moving the lock portion 41 with respect to the cutter supports is during the drilling operation and would result in line contact between the lock portion 41 and lugs 31, rather than the desirable surface contact. The swivel connection prevents the transmi sion of such relative angular movement of the belly hi with respect to the body l5 to the tubular member 35, since the latter is free ter supporting member lugs 31, because of their reater load transmitting capacity, the swivel or oscillatable arrangement between the tubular look member 35 and driving kell 14 also offers an advant ge in connection with a lock ring of circular cross-section, such as disclosed in thy above-referred to patent application. The swivel connection enables the lock ring 41b to rotate during use of the device, and distributesthewear :uniformly around the ring. This arrangement is disclosed in the modification shown in Figure 8 A surface contact may be provided between the circular cross-section ring Alb, since the lugs 31 may also be provided with an arcuate shape of substantially the same radius as the lock ring. Rotation of the ring 4122 within the body would enhance the life of the lock portion of the tubular mandrel 35 materially, by distributing the wear around the entire ring circumference.

Another embodiment of the invention is disclosed in'Figure '9, in which the same type. of swivel .ronnection between the driving kelly I4 -'and tubular member 59 is disclosed; However, in this modification, elastic or spring means are not employedfor initially expanding the cutters 25 outwardly, with the tubularmandrel only being used as a locking device to prevent inward movement of the cutters after they have been expanded outwardly. As shown in Figure 9, the cutters 25 are arranged on their supporting members |9a in substantially ,the same manner as in the other form of the invention. A downwardly and inwardly tapered expander is provided on the bottom end of the tubular member 5|] for cooperation with correspondingly tapered surfaces 52 on the inner portions of the supporting members lilo.

The cutters may be held in an inward position initially by a latch strip 45, in thesame manher as the other arrangements, and upon the drilling tool being lowered on the string of drill pipe B to the bottom F of the well bore, and with the pilot bit Ill resting on the hole bottom, the

pumps maybe started at the surface of the well bore to cause the fluid exhausting from the tubular member 51! to blow the latch strip off the :-hook ends 43 of the latch device. Then the tool :is rotatedand drilling weight imposed downwardly on the drill pipe B and kelly M to rotate the body I51: and cutters 25 around the axis of the bore. During such rotation the keily I4 is gradually fed downwardly and -the tubular member with i s tapered expander 5| is also forced downwardly, shoulders Mo, 39,- to drive the tapered expander or wedge 5| down along the tapered surfaces 52 of the supporting members l9a, urging them gradually outwardly until the lower end 48 of the kelly engages the guide washer 49, which limits the extent 'of downward movement of the tubular member and expander. Rotary movement .i may be continued and the proper drilling weight imposed in order to enlarge the hole being drilled by the pilot bit ||lto the required diameter.

The tapered expander 5| may have fiat faces 5|a to cooperate with corresponding fiat or tapered faces 52 on the supporting members |9a, offering a large bearing surface resisting inward movement of the cutters 25, or, if desired, the "cross-section of the expander 5| may be circular. In any event, the swivel arrangement between the expander and lock device 5|] and the driving kelly I4 enables an automatic adjustment to take place, insuring most effective bearing con-.

. tac t. bfitween'the expander 5| and its cooperable "support ing; men rbers |9a. The necessity for r n m i ns. an illing. torq through st aeeredsaeae cai La rpus o ins because of the abutting ;members 19a for the cutters is alsoobviated, 'g which as"mentioned above, would; disrupt the 9i .be'd ir ne itcs cm re th drill n #25 weight immediately al ows the-retractor spring 38 to shift the body |5b of the tool downwardly with respect to the expander 5|, elevating the expander 5| with respect to the supporting members So, and permitting inward retraction oi. the

cutters 25 during upward movement of the-well tool through the well casing.

Havin thus described my invention, what I 10 claim and desire to s cure by Letters Patent-is:

pe ans engaging said cutter means for ex anding said cutter means lateral y outward, a lock device movable in one longitudinal direction along said body to a position preventing inward movein said cutter means lat rally outward. a lock d vice movable in one longitudinal direction along said body to a position preventing inward movement of said cutter means from its outwardly expanded position. said lock device conibrising a one-piece first member solined to said bodv and a second member rotatablv su ported wit in said first member and enga eable. with said cutter means, said members having op osed en aging surfaces defining supporting means within said first member.

. A rotary well drilling bit; incl ding a body,

cutter means mounted on said body, means enga ab e with said c tter means for expanding and holding said cutter means laterally outward, comprisi a first member connectable to a drill string and slidably splined to'said body, a second -memb=-'r rotatable within said first member and engageable with said cutter means for holding said cutter means laterally outward, said second member extending through said first member from its point of connection with the drill string, means on said second member at said point" of connection with said dri l string in'abutting contact with said first member for preventingsubstantial relative longitudinal movement between said members in one direction while permitting relative rotation therebetween, and means on one of said members coengaging with means on the other of said members preventing substantial relative longitudinal 'movement between said members in the opposite direction whole permitting relative rotation therebetween.

4. A rotary well drilling bit, including a body, cutter means mounted on said body for lateral expansion with respect to said body. means for expanding and holding said cutter means laterally outward, comprising a one-piece first member connectible to a drill string and slidably .splinedyto said body; a second member piloted outward, said members having laterally disposed relatively .movable portions in contacting rela- .tionshiprswivelly connecting said..members together, and spring means; betweensaidbodyiand 9 the second of said members for shifting said second member to a position permitting retraction of said cutter means with respect to said body.

ARCHER W. KAMMERER.

REFERENCES CITED The following references are of record in the file of this patent:

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